


Anatomy Homework

by Strayhaven



Category: Star Trek, Star Trek: Alternate Original Series (Movies)
Genre: Alien Biology, Established Relationship, First Time, M/M, Mind Meld, Plot What Plot/Porn Without Plot, Praise Kink, T'hy'la
Language: English
Status: Completed
Published: 2013-08-12
Updated: 2013-08-12
Packaged: 2017-12-23 05:07:26
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,764
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/922361
Author URL: https://archiveofourown.org/users/Strayhaven/pseuds/Strayhaven
Summary: <blockquote class="userstuff">
              <p>Kirk gets a surprise from Spock.  Basically smut.  There is a bit of love and romance talk though.</p>
            </blockquote>





	Anatomy Homework

“Give me a minute, Spock.” Spock looked down at himself, sheathed almost fully inside Jim Kirk. He felt his organ twitch in arousal, and a low moan escaped from Jim. “Shit, you feel big.” Spock did not respond verbally, but pushed the rest of the way into his partner. “Fuck!” Spock instinctively grabbed Kirk's hips as he tried to move away from the intrusion.

“It had been a minute, Jim.” Spock ran a hand down the smooth back below him. Kirk shuddered. Spock enjoyed the man's responsiveness.

“It doesn't usually mean...never mind. I'm good now.” Jim shifted below him, ran a hand down his cock. Spock waited. Jim looked over his shoulder at Spock. “Spock?”

“You must begin clenching now, Jim.” Spock felt his Captain's confusion through his fingertips. 

“Doing what now?” 

“You told me you were familiar with Vulcan physiology.” Jim sighed into his pillow before speaking.

“Yeah, I mean, I read a bit.” Spock rotated his hips slightly and Jim moaned in surprise. 

“You are like a child who has not done his homework.” 

“Really would be better if you didn't call me a child right now, Spock.” Kirk began to laugh but a gasp cut through the sound. “Shit, did you just get bigger?” 

“I did, and will continue to do so. I can do so on my own, however, your assistance would be pleasurable.” Spock moved his hands to Jim's hips and circled his own again. His captain hissed below him. 

“Okay, okay. Clench, right?”

“Correct.” Spock moaned as Jim finally began to grip him more tightly. Jim huffed out a breath and shifted up onto his hands rather than his elbows. He clenched again, and Spock was overwhelmed with the pleasure. “Jim-” He moaned as his captain squeezed twice in quick succession. He was a more capable lover than Spock had allowed himself to imagine. He felt himself swell inside his partner, and Jim let out a small shout and tried to move up the bed. Spock's reflexes were quicker, and he again grabbed the slim hips and held firmly. Jim took a steadying breath and neither man moved for a few moments. 

“This never came up in anything I read.” Kirk pushed back slightly and Spock gasped. Jim moaned in pleasure as he felt Spock grow. 

“It is to increase the chances of conception in Vulcans, Captain. The swelling prevents sperm from escaping the female's canal.”

“Please stop talking, Spock.” Jim clenched, and it had the desired effect. Spock gasped and stopped talking, but he also increased in diameter enough to worry Jim. Spock sensed his worry and wrapped a hand around the human cock hanging below them. Jim shuddered then moaned, clenched again involuntarily. Spock reacted by swelling again, and Jim let out a startled gasp as he squirmed. 

“Spock, please, it's too big. I can't-”

“You can, and you will, Jim. I have been looking forward to this for quite some time. I do not plan to stop as I wish to ejaculate inside you.” Spock felt himself grow again, and Jim let out a pained cry. 

“Please don't ever say ejaculate again. Oh god, Spock, how much bigger will you get?” Jim's back was rising and falling rapidly as he took deep breaths. Spock placed his hands there to establish a connection. His captain was in pain, naturally, but was also very much aroused. 

“I will reach a diameter of three inches and a length of eight, Jim.” 

“Fuck no, no! Out, please Spock.” Jim was writhing beneath him, and the movement felt wonderful to Spock. He grew again and noticed the tears as they left Jim's eyes. He touched the back of his lover's neck to steady him.

“Please calm down. I have only a small amount left to grow. I was told it is a manageable size for the human body. I will meld us and the pain will lessen considerably for you, Jim.” Spock moved a hand toward Jim's psi points. 

“Wait, Spock. It won't be the same, I won't be as present, right?” Spock nodded then remembered Jim could not see him. 

“Correct, but you will still have sensation and experience pleasure, as well as orgasm.”

“No, no meld.”

“Jim?”

“After, do it after, I just...I can do this. I want to be fully aware.” Spock touched his lover's neck again, noticing that he was in less pain, but his emotions were much more tumultuous. 

“Are you certain?” Jim clenched around him in response and they both let out surprised moans.

“Certain. Oh god, Spock.” Jim let out a shuddered breath and dropped down to his elbows.

“You are doing very well, Jim.” Spock praised his Captain, and meant it. He was aware that human anatomy differed considerably from his own in this very important way. He was grateful Jim was willing to allow this. His hand was still on Jim's neck, and he felt a marked increase in arousal from below him. “You feel very pleasurable, and have done very well. I am at my full size.” Jim moaned below him, and Spock realized he enjoyed being praised. Spock would be more than happy to praise his accommodating and determined Captain quite frequently. 

“Spock, are you, are you going to move?” 

“That will not be necessary.” Spock grasped his partner's hips and leaned up to kiss the top of his back. Jim huffed out a laugh. 

“How do I get off, Spock?” Jim reached down to his cock as he spoke, and started to pleasure himself. Spock took his hand in a strong hold and held both at his sides. He leaned close to Jim's ear.

“Do you doubt my ability to bring you to orgasm, Captain?” Spock felt his cock pulse inside Jim and knew he himself was close to completion. Jim shivered and shook his head. “Perhaps you would like to clench again?” Jim shook his head in the negative and whimpered. 

“I don't think I can, Spock.” He reached for his lover's neglected cock, flushed and hard between his legs. He grasped it firmly and Jim jumped in surprise. “Shit, shit. Please!” 

“Clench, Jim.” Spock squeezed his captain but didn't provide the stroking movements he knew would bring relief. He gasped as Jim complied with his demand, and he stroked as a reward. “Good, Jim.” Jim moaned, long and loud, and thrust back into Spock. He clenched again and Spock gasped. “You are very good at this, my love. You are sure no other Vulcan has claimed you before? Perhaps instructed you in our ways?” Spock squeezed Jim harder than would be comfortable, and Jim trembled and whimpered for him. 

“No! No, Spock, only you!” The Vulcan was surprised at his possessive behavior, but did not think it an appropriate time for self-analysis. He rewarded Jim by stroking him fast and hard. “Please, please, fuck, don't stop.” Spock felt Jim clench around him once more, and he roared with orgasm. Jim shouted out in surprise beneath him. Spock tried to catch his breath as he relaxed. He wrapped his arms around Jim's lighter body and pulled them onto their sides, spooning. He reached down to help Jim finish. He enjoyed the moans and sighs he received in response as he gently brought his partner to orgasm. He touched Jim's psi points and they both gasped as they melded. He felt his captain orgasm as their minds met. 

“Spock?” Spock was running a hand down Jim's side, feeling surprisingly tactile after their union of body and mind. 

“Yes, Jim?” He inhaled his lover's scent and pulled him back against his chest. 

“Well, two questions, I guess. Three, maybe?” Jim grabbed his hand and laced their fingers together. Spock gasped.

“Is now the time, t'hy'la?” 

“Okay, four questions. First one, at least, really important.” Jim shifted against him. “Are you going to, um. Is it going to get smaller again?” Spock had forgotten that Jim had not done the proper research. 

“You really must read the information I ask you to. I will remain this size for roughly ten more minutes. I can withdraw, if you wish-”

“-No! No, we'll wait.” Jim shifted backwards into him and Spock gasped. He was becoming aroused again, and he was quite certain the human body beside him was at its limit. 

“I suggest you remain still unless you are prepared to repeat our coupling very soon.”

“Right. Got it. You're being really, um, sappy, is I guess the word I want? That's the second question.” 

“Vulcans are not allowed a post-orgasmic glow?” Jim let out a loud laugh, and Spock couldn't stop the smile in response. 

“Oh my god. You never fail to surprise me. Okay, really important. T'hy'la?” 

“My friend, brother, lover.” Spock ran a hand down Jim's face, catching fleeting glimpses of emotions. Love, contentment, excitement, nervousness. He kissed Jim's neck. Jim sighed. 

“Me too, Spock.” They fell into sleep still wrapped up in each other, but slept only briefly. Jim woke with a groan as Spock pulled out from his very sore hole. “Fuck. Warn a guy.” 

“Apologies, Jim. I thought you were sleeping more deeply.” Jim turned to face Spock and their eyes met. Bright blue eyes lit up with a smile. 

“Hey.” 

“Captain, I see no need for greetings, we have been in each other's company for roughly forty-five minutes.” He was pleased to see Jim smile even more in return. He felt his happiness show through his eyes, and knew his partner could see it. 

“So. Your cock is terrifying.” 

“You seemed to enjoy it.”

“Oh, most definitely. Best thing I've ever, ever, done. But doesn't make it not terrifying.” Spock touched Jim's psi points briefly and found him to be completely truthful. Humans were still sometimes confusing. “Oh my god!” Spock flinched, Jim seemed to forget about his Vulcan hearing. “Did you talk to Bones about this?” Spock checked himself from recoiling.

“Absolutely not. He does not need to be any more involved in our lives than he already is.” 

“Jealous Spock. I think I like it.” Spock huffed in response to Jim's cavalier teasing. 

“You liked it very much when I was inside you.” He watched as human pupils dilated, and Jim's heart rate increased. He smiled. 

“You said you were told it was manageable for a human. You swear you didn't talk to Bones?” 

“Vulcans do not lie, Captain.” Jim laughed aloud and rolled on top of Spock. He kissed him on the mouth, then began to kiss his fingertips. Spock squirmed and felt his arousal begin. “I asked M'Benga.” 

“Spock!”

**Author's Note:**

> Originally didn't know if I was writing TOS or Reboot, but near the end think it became reboot because of Spock. If you squint it could maybe be either. A testament to everyone that I think they are really quite interchangeable most of the time. (Definitely not all though)


End file.
